Core winding apparatus



March 17, 1970 B. MOORE CORE WINDING APPARATUS 2 Sheets-Sheet 1 Filed Jan. 26. 1967 INVENTOR B11LL Maoms ATTORNEYS March 17, 1970 MOORE 3,500,878

CORE WINDING APPARATUS Filed Jan. 26, 1967 2 Sheets-Sheet 2 INVENTOR Bl/ELL Mao/es ATTORNEYS United States Patent 3,500,878 CORE WINDING APPARATUS Buell Moore, Houston, Tex., assiguor to Esquire, Inc., New York, N.Y., a corporation of Delaware Filed Jan. 26, 1967, Ser. No. 611,869 Int. Cl. B21f 3/00; H01f 7/06 US. Cl. 14092.2 3 Claims ABSTRACT OF THE DISCLOSURE A supply spool supplies a strip of coil or core material through idle rollers and around a tension roller to a winding mandrel. A terminal attaching device is swingable into position to attach terminals to the end or intermediate points on the strip. The mandrel is rotated to wind a coil or core with a rectangular opening. A pressure roller is urged against the strip as it is wound on the mandrel. The pressure and tension rollers are controlled by pneumatic or hydraulic actuators.

This invention relates to methods and apparatus for forming magnetic cores and electrical coils and more specifically to methods and apparatus for forming electrical windings or magnetic cores having rectangular openings therein for transformers and other inductive devices.

In the manufacture of transformers and similar inductive devices it has been found highly desirable to form a plurality of rings of magnetic or electrically conductive material thus forming a plurality of magnetic cores or electrical coils, each having a rectangular opening therein, and to thereafter assemble these elements into a complete inductive device by continuously winding a core or coil through the plurality of rings. In my copending US. application Ser. No. 466,406 filed June 23, 1965, now abandoned, an apparatus is described for forming a ring through the openings in a plurality of preformed cores or coils, each of which has a rectangular opening. If the plural devices are coils, the ring formed therethrough is formed from a strip of magnetic material of relatively great and indefinite length, the strip being sequentially threaded through the rectangular openings and continuously rotated by the winding apparatus to form a complete core which is rectangular in cross section and which substantially fills the rectangular openings in the preformed coils. Clearly, the preformed devices having rectangular openings could be cores, in which case the material to be threaded therethrough is characterized by high electrical conductivity rather than high magnetic permeability and forms the coil or winding for the completed apparatus.

In that application it was assumed that the preformed elements were manufactured in some conventional manner such as by hand winding or the like. Each coil can comprise two or more individual windings to act, for example, as the primary and secondary windings of the transformer. The core can be in one part or in several parts resembling either two links .of a chain coupled together or several links coupled to one link.

In either case, in devices designed to handle substantial amounts of power, it is highly desirable that both the core and coil be formed from continuous strips of material, the core being formed of a high permeability magnetic material and the coil of a highly electrically conductive material. Each coil can be formed in the shape of a ring, in which case the core passing through the opening therein should have a rectangular opening for optimum magnetic coupling with each coil. Alternatively, the coils can be formed with rectangular openings and the core can be circular, broadly resembling a toroid, the cross section of 3,500,878 Patented Mar. 17, 1970 the core being uniformally rectangular to match the coil openings.

The prior art includes relatively expensive and cumbersome methods and apparatus for forming coils and cores having rectangular openings, such as hand winding or, in the case of cores, of assembling precut laminations. In addition to the disadvantages of expense, lack of consistent repeatability and consumption of time, the technique of assembling precut laminations gives rise to losses in the gaps which necessarily occur at abutting ends of the laminations.

Broadly described, the invention includes a method of producing a wound coil including the steps of securing to one end of a strip of electrically conductive material an electrical conductor, wrapping the strip on a collapsible mandrel having outer dimensions equal to the dimensions of the rectangular opening in the completed coil while maintaining pressure against the strip to cause the strip to follow the contour of the mandrel, severing the strip, attaching an electrical connector to the severed end of the wrapped strip portion, placing an insulator around the wrapped strip, and collapsing the mandrel to facilitate removal of the coil. If desired, the process can be repeated before the mandrel is collapsed and the coil removed, thus forming two or more concentric windings in a single coil assembly. Following removal, the assembly can be heated to anneal the material to reduce the internal stresses and, therefore, the internal losses. The invention also comprises an apparatus for simply and efficiently performing the above steps including a connector means for securing the connector to the end of a strip, a collapsible mandrel, means for wrapping the strip around the uncollapsed mandrel, and means for applying pressure to force the strip to conform to the shape of the mandrel during wrapping.

In order that the manner in which the foregoing is attained in accordance with the invention can be understood in detail, particularly advantageous embodiments thereof will be described with reference to the accompanying drawings, which form a part of this specification, and wherein:

FIG. 1 is a vertical elevation of a coil winding apparatus in accordance with the invention;,

FIG. 2 is an elevation of an electrical terminal usable in the invention;

FIG. 3 is a side elevation in section of a supply spool usable in the apparatus of FIG. 1;

FIGS. 4 and 5 are a front elevation and a side elevation in section, respectively, of a collapsible mandrel in accordance with the invention;

FIG. 6 is a side elevation of a terminal applying apparatus usable in the apparatus of FIG. 1; and

FIG. 7 is a plan section of the apparatus of FIG. 6.

Referring now to FIG. 1, a mounting plate 1 supports an apparatus used to form rings or coils in accordance with the invention. A spool 2 is mounted for rotation on an axle 3 which is journaled for rotation in an opening in plate 1, the spool being designed to carry a supply of strip material to be used in forming the coil. It will be understood that the term coil as used herein can refer to a ring or coil of either electrically conductive or magnetically permeable material and that the term is not necessarily limited to a current carrying winding for an inductive device. Although the term toroid is frequently used to refer to products of this general type, it will be recognized that the term is accurately used only with reference to a surface generated by the rotation of a plane closed curve about an axis lying in its plane and not intersecting it, or to a body whose surface has a form thus generated (Websters Third New International Dictionary Unabridged, 1966). The strip material 4 is ound partially around an idle roller which is mounted r1 an axle 6, the axle being journaled in a plate 1 for 'ee rotation. The strip is also partially wrapped around 1 idle roller 7 which is similarly journaled on an axle Strip 4 is passed around opposite sides of rollers 5 nd 7 to follow a sinuous path between supply spool 2 nd a tension roller 9. Roller 9 is mounted on an axle 10 hich is journaled for rotation in openings through one 1d of a lever arm 11, the other end of which is mounted u an axle 12 which is journaled for rotation in plate '1. nc end of an actuating rod 13 is pivotally connected an intermediate point in lever 11 so that longitudinal lOtlOll of rod 13 causes lever arm 11 to pivot about Kle 12 through an angle determined by the limits on re motion of rod 13. The other end of rod 13 is conected to the piston of a conventional pneumatic or ydraulic actuating device 14, the cylinder of which is xedly secured to plate 1. Device 14 is equipped with an llet pipe 15 to which pneumatic or hydraulic fluid can a supplied under pressure.

A collapsible rectangular mandrel indicated generally t is mounted on a central axis, not shown in FIG. 1, hich extends perpendicularly through plate 1 and is conected to drive means, not shown in FIG. 1. Mandrel 20 an be driven by the drive means to rotate in a direction 1own by arrow 21. Mandrel 20 has four outer surfaces 'hich define the rectangle of the size and shape desired )r the rectangular opening in a completed coil. Strip can be wrapped around mandrel 20 to form the coil, 1e number of revolutions of the mandrel deter-mining 1e size and characteristics of the final product.

A roller 22 is mounted on an axle 23 which is perendicular to the face of plate 1 and which is journaled )1 free rotation in one end of a lever arm 24, the other rm of lever 24 being pivotally mounted on an axle 25 hich is journaled in and extends perpendicularly through late 1. One end of an actuating rod 26 is pivotally conected at an intermediate point of lever 24, the other end f rod 26 being connected to the movable piston of a neumatic or hydraulic actuator 27 which is fixedly iounted on a plate 1. Device 27 is a conventional fluid ctuator and is provided with an inlet pipe 28 through lhlCh pneumatic or hydraulic fluid can be supplied under ressure to move the piston and the actuating rod 26. It will be recognized that lever 24 can move through an ngle the limits of which are determined in one direcion by contact between roller 22 and the surface of landrel 20 and in the other direction by the limit of etracted longitudinal motion of actuating rod 26 imposed y the physical design characteristics of actuator 27.

A terminal applying device indicated generally at 30 ncludes a C shaped frame 31 one end of which is fixedly mounted to one end of a lever arm 32, the other end of vhich is mounted for pivotal motion about an axial 33. l pneumatic or hydraulic actuator 34 is mounted within be opening of frame 31, one end of the actuator being eated and fixedly secured to an inner surface of the rame and the other being directed toward an opposite nner surface 89 of the frame. An actuating rod 35 is xonnected to the movable piston of the actuator and to a lressure plate 36 which is fixed to and movable with the ictuating rod, plate 36 being movable between the end |f the actuator and the inner surface 89 of frame 31. l compressible or deformable terminal member 37 can we placed between pressure plate 36 and the end of rame 31 and can be deformed by causing plate 36 to nove toward the end of the frame to apply pressure to he terminal. The motion of actuating rod 35 and plate i6 is controlled by the application of fluid pressure through LII inlet pipe 38.

It will be understood that the various rollers and other levices described with reference to FIG. 1 can be mounted for rotary or pivotal motion in any convenient manner yith the axles thereof being fixedly secured to either the mounting plate or the device itself, whichever is more convenient for the particular application.

The operation of the apparatus of FIG. 1 commences with threading the strip 4 around spools 5, 7 and 9 in the sinuous path shown in FIG. 1. During the threading pressure is removed from inlet pipe 15 allowing lever 11 to be rotated downwardly, retracting rod 13 into actuator 14. A terminal 37 is placed'on plate 36 and the distal end of strip 4 is placed into the opening in terminal 37 after which pressure is applied through the inlet pipe 38 to actuator 34, causing rod 35 and plate 36 to move upwardly, deforming terminal 37 between plate 36 and the inner end of frame 31 around the end of strip 4.

With the terminal thus fixed, the end of strip 4 is placed against the lower surface of mandrel and fluid pressure is applied through inlet pipe 28 to actuator 27 causing lever 24 to pivot upwardly pressing roller 22 against strip 4, holding the strip against mandrel 20. The terminal end of strip 4 can then be temporarily taped or otherwise adhered to the surface of mandrel 20. Mandrel 20 is then caused to rotate in the direction of arrow 21 by energizing the drive means connected thereto, thus wrapping a portion of strip 4 around mandrel 20. Mandrel 20 can be rotated for a preselected number of revolutions until a coil of the desired size is obtained. As mandrel 20 is rotated roller 22 is maintained in firm contact with the outer surface of the strip causing the strip to conform to the outer surfaces of the mandrel, thus obtaining a tight, firm coil with a rectangular opening of the size of the mandrel.

As mandrel 20 is rotated it is desirable that the portion of strip 4 between roller 9 and roller 22 be maintained taut. Fluid pressure is therefore applied during the winding process through inlet pipe 15 to actuator 14, causing rod 13 to urge lever 11 upwardly so that roller 9 can exert a force around strip 4 in a direction away from mandrel 20. In order that this tension can be maintained it is desirable to provide a resistive force to supply spool 2 which tends to oppose rotation of spool 2 in the direction in which strip 4 is removed therefrom. For this purpose a friction plate is provided as shown in the sectional view in FIG. 3, wherein the spool 2 is shown mounted on a simple axle 3, the spool having the strip material wrapped thereon. An annular ring of friction material 40 is adhered to the inner surface of spool 2 facing plate 1. A second annular friction ring 41 is urged outwardly against ring 40 by a compression coil spring 42 which presses against ring 41 and the face of plate 1. The frictional force resulting between rings 40 and 41 tends to oppose rotary motion of spool 2 and allows roller 9 to provide tension in strip 4 as it is being Wound on mandrel 20'.

Mandrel 20 is shown in greater detail in FIGS. 4 and 5 wherein it will be seen that the mandrel includes a block 50 having surfaces 51, 52, and 53 defining three surfaces of a rectangular parallelepiped. Front and back surfaces 54 and 55 are shown perpendicular to surface 52, but need not be perpendicular thereto nor parallel to each other. The upper surface of block 50 is inclined and lies in a plane which forms an acute angle with the plane including surface 52. Inclined surface 56 meets a relatively narrow surface 57 which joins surfaces 55 and 56. Upwardly extending ears 58 and 59 protrude beyond surface 57 and form fixed portions of hinges, ears 58 and 59 having holes through which hinge pins 60 and 61 extend.

The fourth surface of the rectangle is provided by a major surface 62 of a fiat substantially rectangular plate indicated generally at 63. The outer dimensions of surface 62 are substantially the same as the dimensions of surface 52 with the exception of notches in two corners of the plate into which cars 58 and 59 extend. One inner surface of each of the notches is provided with a blind hole into which a hinge pin can extend. Plate 63 is thereby pivotally secured to block 50 so that the plate can swing through an angle which includes a position in which surface 62 is parallel to surface 52. When plate 63 is in its parallel position surfaces 51, 52, 53 and 62 are the four rectangular surfaces which form the rectangular parallelepiped about which strip 4 is wound.

Block 50 is also provided with an axle 64 which extends inwardly through surface 55, and which protrudes from surface 55, passes through plate 1, and is connected to the drive means 65 by which the mandrel is rotated. As will be recognized by those skilled in the art, drive means 65 can be an electric or hydraulic motor or any other convenient apparatus for rotating axle 64.

The angular position of plate 63 is established by a linkage system which is assembled in a recess 70, which extends inwardly from surface 54 of block 50, and a recess 71 which extends inwardly from the front edge of plate 63. A link 72 is pivotally mounted in recess 70 by a pin 74 which passes through the lower end of link 73 and into the opposing parallel walls of recess 70. An access hole 75 extends inwardly from surface 53 of block 50 to allow initial insertion of pin 74. Cooperating links 76 and 77 are pivotedly mounted in recess 71 on pins 78 and 79 which extend through the opposed inner walls of recess 71.

Link 73 is pivotedly attached to links 76 and 77 by a pin 80 which extends through the adjacent ends of the three links. A protruding plate 81 extends outwardly from the outer surface of link 73 to provide a means by which link 73 can be grasped and moved.

It will be seen in FIG. 5 that the critical lengths in the link assembly are the distances between the three axes established by pin 74, by pin 80 and by pin 78 and 79. It will further be seen that the sum of these two lengths is greater than the distance between the axis of pin 74 and the axis of pins 78 and 79 when surface 62 is exactly parallel with surface '52. Plate 63 can therefore be locked in a position wherein surfaces 52 and 62 are parallel merely by pressing the gripping plate 81 toward the inner surface of notch 70. At its innermost position the inner surface of link 73 comes to rest in contact with the inner surface of recess 70 and the axis of pin 80 is further away from the plane of surface 54 than is a line between pin 74 and pins 78 and 79. This assembly thereby provides an overcenter linkage which positively establishes plate 63 in the proper position so that surface 51, 52, 53 and 62 define the desired rectangular parallelepiped.

FIGS. 6 and 7 show in greater detail the apparatus for deforming a terminal member to secure it to the end of strip 4. In FIGS. 6 and 7 the actuating cylinder, inlet pipe, and other portions are identified by the same reference numerals used in FIG. 1. It will be seen the lever arm 32 is prevented from pivoting downwardly by a latch member 39 which protrudes from the face of plate 1 and is maintained in the extended position by a coil tension spring 85. To release lever arm 32 and block 31 it is necessary only to grasp latch member 39 and pull against the force of spring 85 to retract the protruding end of latch 39, thereby releasing arm 32 and allowing the apparatus to pivot downwardly so that it is clear of the remaining apparatus when a terminal is not being applied. As previously discussed, application of fluid pressure through inlet pipe 38 applies pressure against a piston 86 in cylinder 34, forcing rod 35 and plate 36 upwardly until terminal 37 is compressed. With the end of strip 4 inserted in terminal 36 before pressure is applied, the terminal is firmly secured to the end of the strip.

It will be noted that block 36 includes a vertically extending groove 87 and that plate 36 includes a tongue 88 which mates with groove 87 and maintains plate 36 in proper alignment with inwardly facing surface 89 of block 31.

Terminal 37 is shown more clearly in FIG. 2 and comprises a flat strip of relatively stiff electrically conductive material such as copper which has been bent along a longitudinal line 90 into an acute angle. Before bending, prongs 91, 92 and 93 are formed in the strip, these prongs being formed by pressing portions of the metal strip along two lines forming a V and then bending the cut portions so that they protrude from one surface of the material. When the strip is thereafter bent, these prongs extend inwardly toward the opposing surfaces. When the end of strip 4 is placed within the angle formed by the strip and when the strip is further deformed the prongs extend inwardly and penetrate strip 4 to establish a good electrical and mechanical connection. Holes 94 and 95 can also be prepunched through strip 37 so that connecting wires can easily be attached to the terminal.

Another form of terminal can be made by cutting the copper strip along line 90 to approximately the midpoint of the strip. With a terminal formed in this way, the winding process can be interrupted and terminals can be attached to strip 4 at any point by inserting the strip between the opposed faces, the strip then passing through the cut. Each terminal applied in this manner can provide an intermediate tap on a transformer winding.

While certain advantageous embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. An apparatus for Winding electrical coils, magnetic cores and the like in substantially rectangular form comprising the combination of a mounting plate;

supply spool means mounted on said plate for rotation in a plane parallel to said plate for carrying a quantity of metallic ribbon;

a collapsible mandrel rotatably mounted on said plate on an axis extending perpendicular to said plate;

said mandrel having a rectangular cross-section in a plane parallel to said plate when uncollapsed, said mandrel having a reducible dimension in a direction parallel to said plate; said mandrel having six plane surfaces lying in six planes which define a parallelepiped, one of said surfaces being pivotally connected to a second one of said surfaces along a common edge, said one of said surfaces being pivotable from a parallel relationship to a third one of said surfaces in the uncollapsed condition of said mandrel to a nonparallel relationship in the collapsed condition, said first and third surfaces being perpendicular to fourth and fifth surfaces and to said plate, said first, third, fourth and fifth surfaces defining said rectangular cross-section, a roller; a first lever mounted for pivoted motion about an axis perpendicular to said plate,

said roller being rotatably mounted on said first lever at a point on said first lever spaced from said axis a distance greater than the greatest cross-sectional dimension of said mandrel;

said axis of pivotal motion of said first lever being spaced from said axis of rotation of said mandrel a distance sufiicient to allow constant contact between the outer surface of said mandrel and the outer surface of said roller;

first pneumatic means for controllably urging said roller toward said mandrel;

a plurality of idle rollers mounted on axes perpendicular to said plate,

said idle rollers being disposed to form a sinuous path for said metallic ribbon between said supply spool and said mandrel; a tension roller; a second lever carrying said tension roller pivotally mounted on an axis perpendicular to said plate,

said tension roller being disposed relative to said mandrel and said idle rollers to create tension in said metallic ribbon when said ribbon is passed over said tension roller and wound on said mandrel and when said second lever is urged in a first direction; and

second pneumatic means for controllably urging said second lever in said first direction.

2. An apparatus for forming a coil of metallic ribbon aving a substantially rectangular opening therein comrising the combination of a collapsible mandrel having a central axis and outer surfaces defining a parallelepiped when uncollapsed,

said mandrel being journaled for rotation about said central axis,

an outer surface of said mandrel being pivotally attached to a second surface thereof to allow reduction of one dimension of said parallelep p said one dimension lying in a plane perpendicular to said central axis;

linkage means pivotally attached to said mandrel for locking said mandrel in the uncollapsed condition; drive means for rotating said mandrel on said central axis;

a spool of metallic ribbon having an axis parallel to said central axis of said mandrel,

said spool being rotatable about said axis; restraining means for applying a force tending to oppose rotation of said spool; first roller means having a first translatable axis; idle roller means defining, with said first roller means,

a sinuous path for the metallic ribbon between said spool and said mandrel,

said first roller means being operative to create tension in said ribbon when said ribbon is placed in said sinuous path; and second roller means having a second translatable axis for holding the ribbon against the outer surfaces of said mandrel when said mandrel is rotated to form a coil. 3. An apparatus according to claim 1 wherein said second, third, fourth, fifth and sixth surfaces bear fixed, unmovable relationships to each other.

References Cited UNITED STATES PATENTS 670,107 3/1901 Lambert 242-1101 X 964,023 7/1910 Hofmann 242-1101 2,767,382 10/1956 Steinmayer 29-605 X 3,049,793 8/1962 Cooper 29-605 3,126,620 3/ 1964 Kubisiak 29-605 3,084,734 4/1963 Richardson 242-9 X 3,162,391 12/1964 Westcott et al. 29-605 X 3,200,476 8/ 1965 Olsen et al. 29-605 JOHN F. CAMPBELL, Primary Examiner CARL E. HALL, Assistant Examiner US. 01. X3. 29 2s.42, 205, 605; 242 9, 72, 110 

